A method combining a traditional laser pump-probe experiment with the detection of high-frequency sound and thermal waves reveals the microscopically bumpy interface between two apparently smooth surfaces.

According to a new theory, the extreme hardness of new layered materials comes from the strength of chemical bonds that are oriented perpendicular to the deforming force, rather than parallel, as might be expected.

Real-world events always proceed in the direction of increasing entropy, even though the laws of physics don’t require it. The reason we never see events that reduce entropy is that they cannot leave behind any evidence of having happened, according to a new theory.

Ultrahigh energy photons striking matter can transform into rho mesons through an interaction that involves many nuclei simultaneously, a phenomenon that may affect the detection signatures of high-energy particles from space.